Missing variables after PostOrderFunctionAttrsPass at Og

[cristianassaiante]

Bugzilla Link	51735
Version	trunk
OS	Linux
CC	@JDevlieghere,@jmorse,@walkerkd,@OCHyams,@pogo59

Extended Description

Upon calling a function from an external module, the variable i passed to it is not visible from lldb. Using -opt-bisect-limit we discovered that the pass causing the symbols disappear is "PostOrderFunctionAttrsPass on SCC (main)".

$ cat a.c

void  a()
{
char l_57 = 1;
int l_63 = 2,  i = 0;
for (; i < 8; i++)
;
test_nop();
test_support_3215(l_57, l_63, i);
}
int main ()
{
a();
}

$ cat lib/test.c

#include <stdio.h>
#include <stdint.h>
#include "test.h"

void test_nop() {
    printf("\n");
}
 
void test_support_3215(int l_57, int l_63, int i) {
    printf("%d %d %d", l_57, l_63, i);
}

$ cat lib/test.h

#pragma once

void test_nop();
void test_support_3215(int l_57, int l_63, int i);

$ clang -v
clang version 13.0.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/8
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.5.0
Candidate multilib: .;@m64
Selected multilib: .;@m64

$ lldb -v
lldb version 13.0.0

clang revision c2c977c
lldb revision c2c977c

$ clang -g -Og -o opt lib/test.c a.c
$ lldb opt
(lldb) target create "opt"
Current executable set to '/home/cristianrichie/159/reduce/opt' (x86_64).
(lldb) b 7
Breakpoint 1: 2 locations.
(lldb) r
Process 4504 launched: '/home/cristianrichie/159/reduce/opt' (x86_64)
Process 4504 stopped

• thread #​1, name = 'opt', stop reason = breakpoint 1.2
  frame #​0: 0x0000000000401161 opt`main [inlined] a at a.c:7:1
  4 int l_63 = 2, i = 0;
  5 for (; i < 8; i++)
  6 ;
  -> 7 test_nop();
  8 test_support_3215(l_57, l_63, i);
  9 }
  10 int main ()
  (lldb) frame var
  (char) l_57 = '\x01'
  (int) l_63 = 2
  (lldb) frame var i
  error: no variable named 'i' found in this frame